Features:Sensitivity/Alarm Time:Within 60~90 minutes at 50ppm CO concentration;Within 10~40 minutes at 100ppm CO concentration;Within 3 minutes at 300ppm CO concentrationLCD Displayer (optional): 4 digits LCD displayerAudibility: 85dB ( at 1m distance )， Frequency 3 - 0.5KHZStandby Current: